From: "David A. Black" <dblack@...>
Date: 2008-09-07T02:46:14+09:00
Subject: Re: attr_*, *variables_*

Hi --

On Sun, 7 Sep 2008, Thomas B. wrote:

> Pedro Silva wrote:
>> I prefer the attr* notation, but what really matters is to have a unique
>> invocation form. Does anyone think the same?
> (Did you mean 'uniform'? Or I don't understand this sentence.)
>
> I agree that it is good to have one standard, but I think that this is
> the case here, more or less. And the standard is to give prefixes when
> we perform an action on a prefixed variable, and in attr_* arguments are
> not prefixed simply because this action (defining accessors) involves
> both the variable, and the newly created method, of which the latter is
> not prefixed. So they chose that you sort of specify the method name and
> not the attribute name.
>
> I agree that writing attr_accessor :@a could be regarded as correct as
> well, because this would let anybody use the form they find more
> coherent with the rest of the methods, and it would seem more clear to a
> beginner (I remember my confusion when I first saw it).

attr_accessor :@a is ultimately confusing, though, because the
attribute is not the instance variable itself; it's implemented with
the instance variable. I know that sounds like splitting hairs, but
it's important. Attribute is a higher-level concept than instance
variable, and it's pieced together in Ruby from instance variables and
methods -- so :@a would be mixing in an implementation detail (as
would :"a()", for example, even though it might evoke the
method-creating side of the attr_* family).


David

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